EMMC OPOS6UL

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OPOS6UL eMMC layout

By default, the 4GB eMMC on OPOS6UL module has 4 physical/hardware partitions:

Boot0 Boot1 RPMB User Data


Name U-Boot name Size Comment
boot0 mmc dev 0 1 4MBytes U-Boot is installed on this partition
boot1 mmc dev 0 2 4MBytes Not used
rpmb mmc dev 0 3 512KBytes Not used
User Data mmc dev 0 0 remaining space (~3,7GBytes) Kernel, device tree and rootfs

Boot0 partition layout

. SPL IMG ... ENV1 ... ENV2 ...
  • Linux device: /dev/mmcblk2boot0
Offset (blocks) Offset (bytes) Size (bytes) Comment
0 0 1 KB (0x400) Free
0x02 1 KB (0x400) 68 KB U-Boot SPL (apf6-u-boot.spl)
0x8a 69 KB (0x11400) 512 KB U-Boot IMG (apf6-u-boot.img)
Free
0x800 (2048) 1024 KB (0x100000) 10 KB (0x2800) U-Boot environment
Free
0xc00 (3072) 1536 KB (0x180000) 10 KB (0x2800) Redundant U-Boot environment
Free

Boot1 partition layout

  • Not used !

RPMB partition layout

  • Not used !

User Data partition layout

There are 3 partitions on the "User Data" physical partition:

... Failsafe/Update (primary) Default Rootfs (primary) Home/Data (primary)


Name U-Boot device Linux device Offset (bytes) Offset (sectors/blocs) Size Comment
MBR NA NA 0 0 512 bytes (1 block) Master Boot Record + some spare space ( -> Don't touch it :-) )
Failsafe mmc 0:1 /dev/mmcblk0p1 1M 2048 (0x800) 128MBytes (262144 sectors) system/rootfs to restore your board in case of problem or setup a safe update mechanism (ext4 formatted)
Rootfs mmc 0:2 /dev/mmcblk0p2 264192 (0x40800) 2GBytes (4194304 sectors) the default booted rootfs is on this partition (ext4 formatted)
Home/Data mmc 0:3 /dev/mmcblk0p3 4458496 (0x440800) Rest of space: ~1,5GBytes (3176448 sectors) HOME can be stored on this partition (ext4 formatted)
  • By default, when flashed from U-Boot, rootfs and boot are only occupying the size of the .ext4 images used during flashing. If you want to increase the rootfs/boot size to all available free space then, after Linux has booted, use the following commands:
# resize2fs /dev/mmcblk0p2        # for Rootfs
  • Or with apf-config command:
# apf-config
  • In menu:
|     1 Expand Filesystem(s)         OS can then use all eMMC/SD space         |

Rootfs/Boot will then be extended to all the "Rootfs"/"Boot" eMMC partitions space.

Tips

  • Commands to partition User Data from fdisk on Host PC with U-Boot UMS. Check /dev/sdc is your OPOS6UL device otherwise you may destroy your PC partition table !!!:
$ sudo fdisk /dev/sdc
n
p
1
2048
+128M
n
p
2
264192
+2G
n
p
3
4458496
7634943
w

$ sudo mkfs.ext4 -O ^64bit /dev/sdc1
$ sudo mkfs.ext4 -O ^64bit /dev/sdc2
$ sudo mkfs.ext4 -O ^64bit /dev/sdc3

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